In the poultry industry, newly hatched chicks are particularly susceptible to Salmonella infection. This bacterium is spread from fecal material, and young animals can become infected from the soil or perhaps from contaminated processed feed, leading to a high mortality rate and concomitant serious economic consequences. In addition to Salmonella, the poultry house environment also maintains large numbers of Escherichia coli (E. coli) through fecal contamination, leading to systemic infection in the poultry via the respiratory tract and intestines. This E. coli infection is referred to as colibacillosis. The resultant bacteremia progresses to septicemia and death, or the infection extends to serosal surfaces, pericardium, joints and other organs. Both E. coli and Salmonella diseases therefore present a serious threat to the poultry industry on a continuing basis.
Treatment and prevention strategies against Salmonella include in ovo vaccination against Salmonellosis, such as that described in U.S. Pat. No. 6,231,871 B1. However, in ovo vaccination can be arduous in large poultry facilities. Many hatcheries lack the sophisticated and specialized egg-vaccinating equipment which is necessary. Regarding E. coli infection, control of predisposing infections or environmental factors and early use of antibiotics is an accepted practice to minimize E. coli presence in poultry houses. Unfortunately, a high frequency of resistance to tetracycline, kanamycin, neomycin, cephalotin, streptomycin and erythromycin has been observed.
Although there is a commercial live E. coli vaccine available for use against colibacillosis in turkeys, there does not appear to be a fully suitable vaccine for use in chickens. Moreover, there appears to be no combination vaccine composition available for protection against both Salmonella and E. coli infections that is safe and effective for poultry, including chickens, and that is suitable for economic administration such as mass application to post-hatch birds via spray or drinking water.
Therefore, it is an object of this invention to provide a safe and effective vaccine composition against infection and disease caused by Salmonella species, including Salmonella typhimurium, as well as against Escherichia coli, in poultry, including chickens.
It is another object of this invention to provide a method for the prevention or amelioration of infection or disease caused by Salmonella species (including S. typhimurium, as well as others such as S. enteritidis and S. heidelberg), and by E. coli in poultry.
It is a feature of this invention that the vaccine composition is suitable for mass application, such as via drinking water or spraying.
It is an advantage of this invention that the live vaccine composition provide both cellular and humoral immunity responses in the host.